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CN-122002825-A - SiC JBS unit and SiC JBS device

CN122002825ACN 122002825 ACN122002825 ACN 122002825ACN-122002825-A

Abstract

The invention discloses a SiC JBS unit which comprises a cathode, an N + substrate, an N ‑ drift region, a P + region and an anode which are sequentially arranged from bottom to top, wherein P region grooves extending downwards are formed in the top of the N ‑ drift region at intervals, the P + region is positioned in the P region grooves, the tops of the N ‑ drift region and the P + region are respectively attached to the anode, a first depletion region is formed in the region, connected with the P + region, of the N ‑ drift region, a second depletion region is formed in the other side, far away from the N ‑ drift region, of the P + region, and the second depletion region is used for limiting the width of the first depletion region. According to the SiC JBS unit, the first depletion layer and the second depletion layer are respectively arranged on two sides of the P + region 4, so that the expansion of the P + region 4 to the depletion layer of the N ‑ drift region 3 is limited, the width of the first depletion layer is reduced, the conductive channel is widened, and the on-resistance of the SiC JBS unit is reduced.

Inventors

  • Yu Hengwen
  • LUO ZHENGRONG
  • LI ZHE
  • WANG XIAOLU

Assignees

  • 安徽瑞纳半导体科技有限公司

Dates

Publication Date
20260508
Application Date
20260309

Claims (9)

  1. 1. The SiC JBS unit is characterized by comprising a cathode (1), an N + substrate (2), an N - drift region (3), a P + region (4) and an anode (6) which are sequentially arranged from bottom to top, wherein P region grooves extending downwards are formed in the top of the N - drift region (3) at intervals, the P + region (4) is positioned in the P region grooves, and the tops of the N - drift region (3) and the P + region (4) are respectively attached to the anode (6); The region where the N - drift region (3) is connected with the P + region (4) is formed with a first depletion region, and the other side of the P + region (4) away from the N - drift region (3) is formed with a second depletion region, wherein the second depletion region is used for limiting the width of the first depletion region.
  2. 2. SiC JBS cell according to claim 1, characterized in that the other side of the P + region (4) remote from the N - drift region (3) is provided with an N + compensation region (5).
  3. 3. SiC JBS unit according to claim 2, characterized in that the tops of the P + region (4) and the N + compensation region (5) are respectively attached to the anode (6), and the N + compensation region (5) is embedded in the P + region (4).
  4. 4. A SiC JBS unit according to claim 3, characterized in that the P + region (4) is arranged in a U-shape, the N + compensation region (5) being located within the U-shaped P + region (4).
  5. 5. SiC JBS unit according to claim 1, characterized in that a spacing d, d being ≡ 0.5 μm is provided between the boundary of the N + compensation region (5) and the boundary of the P + region (4).
  6. 6. The SiC JBS cell of claim 5, wherein the doping concentration of the N + compensation region (5) is less than the doping concentration of the P + region (4).
  7. 7. SiC JBS cell according to claim 6, characterized in that the doping concentration of the N + compensation region (5) is greater than the doping concentration of the N - drift region (3).
  8. 8. SiC JBS unit according to claim 1, characterized in that the thickness of the N - drift region (3) is set to 2-200 μm.
  9. 9. A SiC JBS device comprising a plurality of SiC JBS cells of any of claims 1 - distributed in an array.

Description

SiC JBS unit and SiC JBS device Technical Field The invention relates to the field of semiconductor power devices, in particular to a SiC JBS unit and a SiC JBS device. Background Silicon carbide (SiC) is used as a representative of a third generation wide bandgap semiconductor material, and exhibits remarkable advantages in high temperature resistance, high voltage resistance, high frequency operation and radiation resistance by virtue of the intrinsic characteristics of wide bandgap, high critical breakdown field strength, high thermal conductivity and the like. In SiC power devices, a junction barrier schottky diode (JBS) is a commonly used structure. The structure combines the advantages of low forward conduction voltage drop of a Schottky diode (SBD) and high voltage resistance and low electric leakage of a PN junction diode, and is the main stream choice of the current medium-high voltage SiC power rectifier. However, the existing SiC JBS structure still has a technical bottleneck in practical application. Specifically, conventional JBS structures typically employ periodic, discontinuous p+ implant regions, i.e., p+ island structures, at the active region surface. When the device is turned on in the forward direction, the P+ regions and N-drift regions at the two sides and the bottom of the P+ regions form PN junctions. The PN junction generates a built-in electric field in a conducting state, and then a space charge region, namely a depletion layer, is formed in the N-drift region. The presence of the space charge region results in a narrowing of the physical channel through which current flows, creating a JFET effect, thereby increasing the forward on-resistance of the device. The increase of the on-resistance can directly lead to the increase of the forward on-voltage drop of the device under the rated current, which not only increases the on-loss of the device, but also seriously reduces the rated current capacity of the device and limits the application of the device in the occasion of larger current. Disclosure of Invention The invention aims to provide an SiC JBS unit and an SiC JBS device, wherein the SiC JBS unit is provided with a first depletion layer and a second depletion layer which are respectively positioned at two sides of a P + region 4, so that the expansion of the depletion layer of the P + region 4 to an N - drift region 3 is limited, the width of the first depletion layer is reduced, the conducting channel is widened, and the on-resistance of the SiC JBS unit is reduced. In order to achieve the above purpose, the invention provides a SiC JBS unit, which comprises a cathode, an N + substrate, an N - drift region, a P + region and an anode which are sequentially arranged from bottom to top, wherein P region grooves extending downwards are arranged at intervals on the top of the N - drift region, the P + region is positioned in the P region groove, and the tops of the N - drift region and the P + region are respectively attached to the anode; The region where the N - drift region is connected with the P + region is formed with a first depletion region, and the other side of the P + region away from the N - drift region is formed with a second depletion region, wherein the second depletion region is used for limiting the width of the first depletion region. Preferably, the other side of the P + region away from the N - drift region is provided with an N + compensation region. Preferably, the tops of the P + region and the N + compensation region are respectively attached to the anode, and the N + compensation region is embedded in the P + region. Preferably, the region P + is arranged in a U shape, and the region N + is located in the region P + in the U shape. Preferably, a distance d is arranged between the boundary of the N + compensation region and the boundary of the P + region, and d is more than or equal to 0.5 mu m. Preferably, the doping concentration of the N + compensation region is less than the doping concentration of the P + region. Preferably, the doping concentration of the N + compensation region is greater than the doping concentration of the N - drift region. Preferably, the thickness of the N - drift region is set to be 2-200 μm. The invention also provides a SiC JBS device which comprises a plurality of SiC JBS units distributed in an array. According to the technical scheme, the first depletion layer and the second depletion layer are respectively formed on the two sides of the P + region, and holes in the P + region are consumed by the first depletion layer and the second depletion layer, so that the width of the first depletion layer can be effectively reduced by arranging the second depletion layer, the width of a circulation channel is increased, and on-resistance is reduced. Therefore, the first depletion layer and the second depletion layer are respectively arranged on two sides of the P + region, so that the expansion of the depletion layer from the P + r